有没有一种快速的方法来拆分一个（非常）长的方程式？

Question

我正在从 Mathematica 生成 LaTeX 代码，我必须将其插入到我的输入 .tex 文件中。问题是方程式太长，无法在页面上显示，而且拆分它们需要很长时间。有没有办法快速拆分这么长的方程式？

输入如下：

\left(
  \epsilon ^1 \phi _1+ \epsilon ^2 \phi _2 + \epsilon ^3 \phi _3 +\epsilon ^4 \phi _4+
  \epsilon ^5 \phi _5+\epsilon ^6 \phi _5+\epsilon ^7 \phi _5+\epsilon ^8 \phi _5
\right)
+g_2 \left(
  \epsilon ^1 \phi _1+ \epsilon ^2 \phi _2 + \epsilon ^3 \phi _3 +\epsilon ^4 \phi _4+
  \epsilon ^5 \phi _5+\epsilon ^6 \phi _5+\epsilon ^7 \phi _5+\epsilon ^8 \phi _5
\right){}^{\wedge}2
+g_3 \left(
  \epsilon ^1 \phi _1+ \epsilon ^2 \phi _2 + \epsilon ^3 \phi _3 +\epsilon ^4 \phi _4+
  \epsilon ^5 \phi _5+\epsilon ^6 \phi _5+\epsilon ^7 \phi _5+\epsilon ^8 \phi _5
\right){}^{\wedge}3
+ g_4 \left(
  \epsilon ^1 \phi _1+ \epsilon ^2 \phi _2 + \epsilon ^3 \phi _3 +\epsilon ^4 \phi _4+
  \epsilon ^5 \phi _5+\epsilon ^6 \phi _5+\epsilon ^7 \phi _5+\epsilon ^8 \phi _5\right){}^{\wedge}4
+g_5 \left(
  \epsilon ^1 \phi _1+ \epsilon ^2 \phi _2 + \epsilon ^3 \phi _3 +\epsilon ^4 \phi _4+
  \epsilon ^5 \phi _5+\epsilon ^6 \phi _5+\epsilon ^7 \phi _5+\epsilon ^8 \phi _5\right){}^{\wedge}5
+g_6 \left( 
  \epsilon ^1 \phi _1+ \epsilon ^2 \phi _2 + \epsilon ^3 \phi _3 +\epsilon ^4 \phi _4+
  \epsilon ^5 \phi _5+\epsilon ^6 \phi _5+\epsilon ^7 \phi _5+\epsilon ^8 \phi _5\right){}^{\wedge}6
+g_7 \left(
  \epsilon ^1 \phi _1+ \epsilon ^2 \phi _2 + \epsilon ^3 \phi _3 +\epsilon ^4 \phi _4+
  \epsilon ^5 \phi _5+\epsilon ^6 \phi _5+\epsilon ^7 \phi _5+\epsilon ^8 \phi _5\right){}^{\wedge}7
+g_8 \left(
  \epsilon ^1 \phi _1+ \epsilon ^2 \phi _2 + \epsilon ^3 \phi _3 +\epsilon ^4 \phi _4+
  \epsilon ^5 \phi _5+\epsilon ^6 \phi _5+\epsilon ^7 \phi _5+\epsilon ^8 \phi _5
\right){}^{\wedge}8

Answer 1

所有这些\left使\right公式不可拆分。如果您的公式都具有该格式，则可以这样做：

\documentclass{article}
\usepackage{lipsum} % just for the example

\newenvironment{mathematica}
 {\begin{quote}%
  % neutralize \left and \right
  \def\left{}\def\right{}%
  % add some space around operation signs
  \medmuskip=4mu plus 2mu minus 2mu
  % correct the horrible ^{\wedge}<exponent>
  \def\wedge{\aftergroup{\aftergroup}\aftergroup^}%
  $}
 {$\end{quote}}

\begin{document}

\lipsum*[3]
\begin{mathematica}
\left(\epsilon ^1 \phi _1+ \epsilon ^2 \phi _2 + \epsilon ^3 \phi _3 +\epsilon ^4 \phi _4+\epsilon 
^5 \phi _5+\epsilon ^6 \phi _5+\epsilon ^7 \phi _5+\epsilon ^8 \phi _5\right)+g_2\left(\epsilon 
^1 \phi _1+ \epsilon ^2 \phi _2 + \epsilon ^3 \phi _3 +\epsilon ^4 \phi _4+\epsilon ^5 \phi 
_5+\epsilon ^6 \phi _5+\epsilon ^7 \phi _5+\epsilon ^8 \phi _5\right){}^{\wedge}2 
+g_3\left(\epsilon ^1 \phi _1+ \epsilon ^2 \phi _2 + \epsilon ^3 \phi _3 +\epsilon ^4 \phi 
_4+\epsilon ^5 \phi _5+\epsilon ^6 \phi _5+\epsilon ^7 \phi _5+\epsilon ^8 \phi 
_5\right){}^{\wedge}3 + g_4\left(\epsilon ^1 \phi _1+ \epsilon ^2 \phi _2 + \epsilon ^3 \phi _3 
+\epsilon ^4 \phi _4+\epsilon ^5 \phi _5+\epsilon ^6 \phi _5+\epsilon ^7 \phi _5+\epsilon ^8 
\phi _5\right){}^{\wedge}4+g_5\left(\epsilon ^1 \phi _1+ \epsilon ^2 \phi _2 + \epsilon ^3 \phi 
_3 +\epsilon ^4 \phi _4+\epsilon ^5 \phi _5+\epsilon ^6 \phi _5+\epsilon ^7 \phi _5+\epsilon ^8 
\phi _5\right){}^{\wedge}5+g_6\left(\epsilon ^1 \phi _1+ \epsilon ^2 \phi _2 + \epsilon ^3 \phi 
_3 +\epsilon ^4 \phi _4+\epsilon ^5 \phi _5+\epsilon ^6 \phi _5+\epsilon ^7 \phi _5+\epsilon ^8 
\phi _5\right){}^{\wedge}6+g_7\left(\epsilon ^1 \phi _1+ \epsilon ^2 \phi _2 + \epsilon ^3 \phi 
_3 +\epsilon ^4 \phi _4+\epsilon ^5 \phi _5+\epsilon ^6 \phi _5+\epsilon ^7 \phi _5+\epsilon ^8 
\phi _5\right){}^{\wedge}7+g_8\left(\epsilon ^1 \phi _1+ \epsilon ^2 \phi _2 + \epsilon ^3 \phi 
_3 +\epsilon ^4 \phi _4+\epsilon ^5 \phi _5+\epsilon ^6 \phi _5+\epsilon ^7 \phi _5+\epsilon ^8 
\phi _5\right){}^{\wedge}8
\end{mathematica}
\lipsum[4]

\end{document}

Answer 2

这只是你问题的一个边缘问题，但请不要让你的读者也这么认为；我在解析你的数学表达式时差点睡着了。为什么不使用求和的方式，以更紧凑的形式来写呢？

\documentclass{article}

\usepackage{amssymb}

\begin{document}
\[  
    \left(
        \sum_{j=1}^4 \epsilon^j \phi_j +
        \left(
            \sum_{k=5}^8 \epsilon^k 
        \right) \phi_5
    \right)
    + \sum_{i=2}^8 g_i
    \left(
        \sum_{j=1}^4 \epsilon^j \phi_j +
        \left(
            \sum_{k=5}^8 \epsilon^k 
        \right) \phi_5
    \right)^i
\]

\vspace{3em}
\noindent
Alternatively:
\[
    x + \sum_{i=2}^8 g_i x^i \,,
\]
where
\[
    x \triangleq
    \sum_{j=1}^4 \epsilon^j \phi_j +
    \left(
        \sum_{k=5}^8 \epsilon^k 
    \right) \phi_5 \,.
\]
\end{document}